Abstract: A method of controlling a pipetting process for a liquid by the use of a pipetting device is suggested, the pipetting process including a calibration process and a dosing process being performed in accordance with a set of process variables wherein, before starting the dosing process for the liquid, the calibration process is carried out to determine the set of the process variables specifically for the liquid, the calibration process comprising the steps of: performing a preliminary dosing process for the liquid using a predefined reference set of the process variables, detecting a preliminary time characteristic of at least one state variable of a medium present in the pipetting device during the preliminary dosing process, and comparing the detected preliminary time characteristic of the state variable with a reference time characteristic of the state variable obtained in advance by performing a dosing process for a predefined reference liquid using the reference set of process variables.

Abstract: A liquid-metering device is disclosed, in particular, a pipetting device for aspirating and dispensing liquids. The device comprises a vessel which is at least partially filled with gas and has an opening through which liquid is received or discharged, a gas-pressure-changing device for changing the gas pressure in the vessel, a state-variable-detecting device for detecting at least one state variable of the gas in the vessel, and a control device which activates the gas-pressure-changing device as a function of the state variable detected by the state-variable-detecting device. The control device is a regulating device which, during a regulating time segment between liquid reception and liquid discharge, activates the gas-pressure-changing device as a function of the detected state variable such that the actual gas pressure in the vessel is kept essentially at a predetermined gas pressure.

Abstract: A liquid-metering device is disclosed, in particular, a pipetting device for aspirating and dispensing liquids. The device comprises a vessel which is at least partially filled with gas and has an opening through which liquid is received or discharged, a gas-pressure-changing device for changing the gas pressure in the vessel, a state-variable-detecting device for detecting at least one state variable of the gas in the vessel, and a control device which activates the gas-pressure-changing device as a function of the state variable detected by the state-variable-detecting device. The control device is a regulating device which, during a regulating time segment between liquid reception and liquid discharge, activates the gas-pressure-changing device as a function of the detected state variable such that the actual gas pressure in the vessel is kept essentially at a predetermined gas pressure.